Yeah basically I outline a 3x3 space where I want the villager to go in design (and i leave a space for where in front of the door is for good measure but that's probably not needed) and then I checker MY ENTIRE TOWN so that there isn't a single open 3x3 space, it's all spaces of 1 or 2. And I mean every possible 3x3 space. Because if you're trying to get your houses in a row, the game isn't gonna like putting them so close together so if there's any secluded 3x3 space it's gonna try to stick them there first, in my experience.
When all the ground is checkered, I TT to about 5:55am of the day they're supposed to move in with my mayor, then quit and wait a few minutes so i know the clock has passed 6am and start creating new save files. I check the spots where I want the house to go and if it's not there i exit to the homescreen without saving and start another new safe file. Sometimes the house goes where I want the first try (it's happened once before) and other times it's taken me hours because 1. once I accidentally left some places in town where i checkered wrong and there were 3x3 spaces or 2. tbh sometimes the game will occasionally set the plot on top of designs anyway.
If it's taking me a really long time and really not going where i want and i see it keeps going in about the same place, i check that space (if the plot didn't go there) on the new save file and see if I accidentally left a 3x3. If I did, I set the DS's clock back a few hours, go back in with my mayor and fix it LOL then TT in game back to 5:55 and start over again :')
I hope all that makes sense
- - - Post Merge - - -
I also found this really old thread while googling that kinda helps and gave info that i never really knew before?? I'm not sure if it's 100% right and idek when the WA update came out and if this post was before that/if things have changed since then, but it's something i at least sort of keep in mind anyway just in case (
link)
So something also worth nothing that you'll see in the graphics of that post i linked you is that you cant leave only one space between two houses or other things, it's gotta be two spaces to account for that little halo of needed buffer space around both structures. If that makes sense (sorry this is really long and detailed)